"Most people who become addicted, like me, do so after a prescription for a painkiller following a medical procedure. Once the phenomenon of craving sets in, it is often too late."
The 57-year-old actress went on to urge people to "work harder" and "do everything [they] can" not to "enable" their loved ones who are experiencing similar struggles.
She wrote: "I, like all of you, mourn the passing of a great artist but I also mourn the passing of potential artists past and present, caught in this deadly vise.
"Let's work harder, look closer and do everything we can not to enable and in doing so, disable, our loved ones who are ill.
"This is what it sounds like when we all cry."
This isn't the first time Jamie - who has adopted children Annie, 29, and Thomas, 19, with husband Christopher Guest - has spoken about her addiction.
In 2009, following Michael Jackson's death from acute Propofol intoxication, she wrote another piece in which she admitted she understood his desire for "relief".
She wrote: "I too found painkillers after a routine cosmetic surgical procedure and I too became addicted.
"Mr. Jackson was an addict. It is coming out. Everywhere. He wanted relief and would get it in any name, place or method he could. It was and is a conspiracy of silence and I'm sure there were attempts to intervene and I'm sure his family and friends tried ... but the addict gets what the addict wants, relief from the pain of their life."
- Bang! Showbiz
